1. Field of the Invention
The present invention relates to a method for controlling the quantity of exposure in photographic printing, wherein, in a process of negative and positive photographic printing, a maximum density and a minimum density of a negative photographic film are measured, which are used with tonal signals obtained therefrom to obtain prints printed to have a proper printing density even from a negative film having principal subject density failures.
2. Description of the Prior Art
Conventional methods for controlling the quantity of printing exposure so far known are as follows:
1. A METHOD FOR CONTROLLING THE QUANTITY OF PRINTING EXPOSURE BY MEASUREMENT OF ONLY THE MEAN TRANSMISSION DENSITY OF A NEGATIVE PHOTOGRAPHIC FILM, AND
2. A METHOD FOR CONTROLLING THE QUANTITY OF PRINTING EXPOSURE BY MEASUREMENT OF THE MEAN DENSITY AND THE TONAL DIFFERENCE OF A NEGATIVE PHOTOGRAPHIC FILM.
Conventional methods for controlling the quantity of printing exposure as described above possess various significant disadvantages. That is, in method (1), in which only the mean transmission density of the negative film is measured, the mean transmission density over substantially the entire area of the negative film is measured so that even for the same principal subject (a portrait in most cases), the mean transmission density differs in the case of a negative film which is greatly different in density in the periphery thereof, and accordingly, the printing exposure time will also differ. This results in disadvantages. For example, a portrait in which snow or the sky is a background will generally be a print which has an excessively high density whereas a portrait taken at night using a flash will be a print which has an excessively low density. These disadvantages as noted above result from the utilization in the above-described described method of only the average value of the density irrespective of the mode of density distribution on the negative film.